Drying apparatus.



H. C. EBEL.

DRYING APPARATUS. APPLICATION FILED MAG-10, 1915;

Patented Mar. 21, 1916.

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HERMANN CHRISTIAN E IBEL, OF I-IANOVER, GERMANY.

DRYING APPARATUS.

meme.

' Specification of Letters Patent.

Patented Mar. 21, 1916.

Application filed August 10, 1915. Serial N o. 44,829.

To all whom it may concern:

'Be it lmown that I, HERMANN CHRISTIAN Been, a subject of the King of Prussia,residing' at 29 Asternstrasse, Hanover, in the German Empire, have invented certain new and useful Improvements in Drying Apparatus, of which the following is a specification. My invention relates to drying apparatus and particularly to apparatus fordrying salt and the like easily affected crystalsor other substances. Apparatus hithertofore used for drying such substances consist of an upright casing heated through its side walls. In such apparatus thesubstances to be treated are fed into the apparatus from above and. pass through a series of superposed through-like carriers which revolve about their longitudinal axis and cause the substances under treatment to gradually drop from carrier to carrier and thereby come in contactwith the drying air ascending. Finally, the substances are discharged at the foot of the apparatus.

The object of my invention is to provide an improved heating system for drying apparatus of such construction.

A further object is to improve upon the construction and the disposition of the rotating carriers.

Hitherto, drying apparatus of the described type have been heated by a system of indirect heating in which theheat carrying gases are caused to pass through an inclosed space which is traversed by the tubes through which the drying air is led beforeentering the drying apparatus. In this mannerthe air conducting tubes are heated by the heating gases surrounding them and transfer the heat to the air passing through the tubes. Such a system of heating tubes has been applied, for instance, with a well known apparatus in a separate brick-built chamber in front of the drying shaft. Another apparatus has become known having a separate chamber besides the drying shaft which chamber is traversed by a system ofsteam pipes while the air to be dried, is caused to flow through the heating chamber and around the steam pipes and thereafter enter the dr ving shaftj According to my invention the heating pipes for admitting the drying air 'are placed standing side by side in succession along the outside of the longitudinal side walls "of the driving "shaft andare" in'clsed in chambers through which the heating fluid (flue gas, steam or the like) are caused to flow. Such air admitting tubes may be provided in any desired number in conformity with the required heating surface. By this arrangement of the heating device a favorable exploitation ofthe heat is secured since not only the air admission tubes are heated by the heating fluid but simultaneously the side walls of the drying shaft through which the substances to be dried are passing. Another effect secured by this arrangement lies in the fact that the drying air, in doing its work in the drying shaft, is enabled to continually recuperate the heat it is losing during the drying process, from the heat radiated by the walls of the drying shaft. Thus, a uniform temperature, is maintained in the drying shaft and this is a very important factor in treating easily affected substances, especially such as, for instance salt,

to secure a stable coloration of the same.

As regards the conveying carriers, these consist of shallow double troughs placed one below the other in such a manner that the circumferential traveling paths of two adjacent troughs cross each other. Such a construction and arrangement of the conveying means effects a smooth downwardly directed sliding movement of the conveyed substances and prevents damaging the substances while undergoing the sliding movement. Another result of this arrangement of the conveying carriers is the reduced height of the whole apparatus; the closely disposed conveying carriers which are engaging each other with interior sllding surfaces turn the substances to; be dried over more effectively and in a shorter apparatus. Thus, the drying effectis obtained within a shorter way of travel asin apparatus previously known, wherein the construction of the-carriers, which, for instance, showed the form of hollow shafts provided with ribs, rendered it impossible to have the traveling paths of two adjacent carriers cross each other; hence, the material to be conveyed through theapparatus had to drop a considerable distance to reach the next carrier below, whereas in the novel device according to my invention the material is only subjected to a smooth sliding movement produced in consequence of the shallow double trough form of the conveyers. In apparatus as they have been known hithertofore,

there is always the possibility that subwhich Figure 1 shows in elevation a cross section along the line AB of Fig. 2. Fig. 2 is a sectional side elevation, partly along the line CD, and partly along the line EF, in Fig. 1. Fig. 3 shows details of the preceding figures on an enlarged-scale.

The apparatus consists of an upright casingwhich is narrow and comparatively long, and is composed of a bottom 2, a cover 1, two end walls 3 aud t, and the side walls 5 and 6. In front of both side walls 5 and 6 and extending to the entire height of the same there are disposed tubes 7 shown inclosed by outer, shells 8 and 9. The tubes 7 are open at their upper'ends which terminate withinthe Chamber formed between the outer walls8 and 9 and the walls 10, 11 arranged at'some distance fromthe former. Preferably and in accordance with the amount of the heating surface required the tubes '7 are provided side by side and in succession along the entire length and height of the apparatus and terminate withitheir lower ends within the drying shaft. The

heating gases enter through the tubes 12 the heating chambers inclosed by. the walls 7 5, 6 and 8, 9 and above and below by the plates 13, leaving the chamber at the upper end through the tubes 14. While passing through these chambers the heating gases arefimparting heat to .the tubes 7- and the walls 5, G and 8, 9. The drying air enteringinto the spaces 16 intermediate the walls 8 and 10, and 9 and 11 respectively, as indicated by arrows 15, becomes primarily heated by the heat radiatingfrom the walls a 8. and 9, and passes then through the tubes 7 in'which the air is further heated'within the spaces 18 intermediate the walls 5 and 6,

.30 and'S and .9, respectively. Finally, the air enters-the shaft '19 after having, been increased to the highesttemperatureadmis sible' by. the heating gasescoming directly from the heat'generator and entering at this region the spaces 18 throughthe fiues 12. On the way upward through the drying shaft from which the air escapesthrough the apertures 20, the heat initially carried a by the air and usedup in the drying process gas. or exhaust steam, is given is being continually recuperative from the heat radiation of the inner sidewalls 5 and 6."

By means. of the partition walls 21 and 22 within the heating chambers the heating a positive guidance, .7 V 1 7 V r .The substances .to be dried are fed into in Fig. 3.

- ;.Having thus deseri 'iIclaimisr f V 7 a 1. i In a hot air drying apparatus the com 7 bination of drying shaft, "having conveythe apparatus through the tube 25 intothe distributer 26. Within the casing .of the disposed concave dishes 28 which are conconvex plates 29. At both ends the cohveying carriers are provided with circular plates 80. The carriers are fixedly mounted upon shafts 27 supported in suitable bearings in the end Walls 3 and 4. Theshafts 2'? are provided with toothed wheels 31 at their 6X- tremities. As is shown in Fig. 1, each two adjacent carriers are disposed relatively toward eachv other in sucha manner that when the dishes of one carrier are'standing horizontally the dishes of the other carrier. haveassumed. a; vertical position extending-with one end into the concavity of one dish of. the horlzontal CZLIIIGI', and v1ce' versa.

The

paths of movement of eachtwo adjacent V dishes are thus crossingeach other. Furthelfmore, each two adjacent carriers are revolving in opposite directions; thereby, the

substance undergoing treatment is slowly passed on from carrier to carrier and is constantly being turned over,'thus enabling the drying air entering the drying shaft 19 at the foot and ascending to the escapes 20, to

penetratethe substance intimately in all its i 1 layers and parts,-

As will be seen upon reference to Fig.2.3 J the carriers rnaybe provided with clearing 7 devices serving'to -clear the dishes, while revolving, of substances tending, to become easily in'crusted. Suchi clearing devices may consist of-brushes182 made of steelor other lea suitable material, which brushes may: .,be

mountedupon theconvex plates 29 in such 7 a 'mannerthat' they sweep during'rotation,

the dishes of adjacent CEIIIlBTS. lnstead of at 34 (Fig; 3).

As has been described above; the conveying carriers maybe operated sons to cause two ad acent carriers to f rotate n opposite brushes 32,-resilient cushions 33 may be used, or elastic scraping plates, as illustrated carrier are standingupright," as illustrated r V I' do .not

means of rotating the dishes or the orderin which they are rotated.

ing carriers revolubly mounted therein, "of

means for'heating the drying air and the I dryingshaft. said means comprising heatingi w I chambers adjoining the drying shaft and. separated from same 7 only by its side walls, ,7 a systemof :air conveying tubes-placed so limit tiny self a; .;any particular V v m bed my invention,1what as to traverse said heating chambers and terminating in the drying shaft at the foot of the latter, inlets and outlets in the heating'chambers for the heating fluid caused to flow through said heating chambers, and air conduits leading to the air admission ends of said air conveying tubes.

'2. In a hot air drying apparatus, the combination of a drying shaft, having conveying carriers revolubly mounted therein, of means for heating the drying. air and the drying shaft, said means comprising heating chambers adjoining the drying shaft and separated from same only by its side walls, air admission chambers above said air heating chambers, a system of air conveying tubes placed so as to traverse said heating chambers from said air admission chambers downward and terminating in the drying shaft at the foot of the latter, inlets and outlets in the heating chambers for the heating fluid which is caused to flow through said heating chambers, partition walls within said heating chambers placed so as to guide the heating fluid in a zig-zag course, and air conducting channels extending over the outside walls of said heating chambers,

said air conducting channels being open at their lower ends and terminating in said air admission chambers.

3. In a hot air drying apparatus, the combination of a drying shaft, a system of superposecl conveying carriers therein, each conveying carrier consisting of a pair of oppositely curved dishes interconnected by a pair of concave longitudinal plates and circular end plates and being fixedly mounted upon a shaft revolubly mounted within said drying shaft, with means for heating the drying air and the drying shaft,

said means comprising heating chambers adjoining the drying shaft and separated from same only by its side walls, air admission chambers above said air heating chambers, a system of air conveying tubes placed so as to traverse said heating chambers from said air admission chambers downward and terminating in the drying shaft at the foot of the latter, inlets and outlets in the heating chambers for the heating fluid which is caused to flow through said heating chambers, partition walls within said heating chambers placed so as to guide the heating fluid in a zig-zag course, and air conducting channels extending over the outside walls of said heating chambers, said air conducting channels being open at their lower ends and terminating in said air admission chambers.

=1. In a hot air drying apparatus for easily affected substances, the combination of superposed conveying carriers, each of which consists of a pair of oppositely curved dishes interconnected by a pair of concave plates and circular end plates, shafts mounted within the drying apparatus and carrying said conveying carriers, said shafts being adapted to be revolved from outside the drying apparatus and thereby to rotate said conveying carriers, the superposed carriers being arranged relatively to each other in such a manner that the path of movement of one carrier crosses the path of movement of each adjacent carrier, whereby the substance to be conveyed through the apparatus is given a short smooth sliding movement.

5. In a drying apparatus, the combination of an upright casing, a system of superposed conveying carriers therein, each conveying carrier consisting of a pair of oppositely curved dishes interconnected by a pair of concave longitudinal plates and circular end plates, shafts revolubly mounted within said casing and having said conveying carriers fixedly mounted thereon, means for revolving said shafts, resilient scraping means projecting from said longitudinal connecting plates of the carriers so as to sweep during rotation the dishes of the adjacent conveying carriers, means for heating the drying fluid and said casing, said means comprising heating chambers directly adjoining said drying casing and separated from same only by its side walls, air admission chambers above said air heating chambers, a system of air conveying tubes placed so as to traverse said heating chambers from said air admission chambers downward and terminating in said drying casing at the foot of the latter, inlets and outlets in the heating chambers for the heating fluid which is caused to flow through said heating chambers, partition walls within said heating chambers placed so as to guide the heating fluid in a zig-zag course, and air conducting channels eXtend ing over the outside walls of said heating chambers,I-said air conducting channels being open at their lower ends and terminating in said air admission chambers.

6. In a hot air drying apparatus,- a drying shaft, a system of superposed conveying carriers each carrier consisting of a pair of oppositely curved dishes interconnected by a pair of concave longitudinal plates revolubly mounted within said drying shaft with means for heating the drying air, substantially as described.

In testimony whereof, I aflix my signature in presence of two witnesses.

HER-MANN CHRISTIAN EBEL.

Witnesses:

L. V. LAHN, THEA KoRr.

Copies of this patent may be obtained for five cents each, by addressing the Commissioner of Patents,

7 Washington, D. G." 

